Expansion system for engine coolant



Dec. 18, 1962 H. L. WARD 3,068,846

EXPANSION SYSTEM FOR ENGINE COOLANT Filed Feb. 27, 1961 20 HEAT,

E- a 33 i5 u 7 I5 L2 la 20 HEAT lo J i kfi zxcr-mmem INVENTOR. Ha'rold L.Wa'rd BY ATTORNEYS 3,068,846 EXPANSIGN SYSTEM FOR ENGENE CGGLANT Harold L. Ward, Peoria, EL, assignor to Caterpillar Tractor (30., Peoria, ili., a corporation of California Filed Feb. 27, 1961, Ser. No. 91,677 1 (Ilaim. (Cl. 123-411) This invention relates to engine cooling systems and particularly to a system that provides for expansion of fluid coolant in a structure which does not exceed the height of the engine. In many engine installations, of which marine installations provide a good example, space is limited and it is desirable that the cooling system and other appurtenances of the engine do not exceed the basic profile of the main engine structure and this is particularly true in the vertical dimension.

Expansion tanks are used in cooling system to accommodate the increased volume of the cooling fluid caused by the heat of engine operation. Unless such tanks are disposed to exceed the height of the engine the cooling system cannot be completely filled without also filling the tank. Engine manufacturers using low tanks are experiencing difficulties with spillage. Spillage detracts from the general appearance and cleanliness of the engine and its compartment, and coolant containing anti-freeze agents is undesirable in bilges because of its tendency to evaporate slowly. Furthermore, without space for expansion any vent in the system permits loss of coolant.

It is an object of the present invention to provide an expansion tank for an engine cooling system which may be disposed below the highest part of the engine and particularly the top of the cylinder head but will insure adequate space for expansion of engine coolant under all operating conditions.

Further objects and advantages of the invention are made apparent in the following specification wherein reference is made to the accompanying drawing illustrating a preferred form of the invention.

In the drawing:

FIG. 1 is a schematic view in :front elevation of an engine showing the externally disposed parts of its cooling system;

FIG. 2 is a fragmentary sectional view taken on the line IIII of FIG. 1; and

FIG. 3 is a fragmentary sectional View taken on the line IIIIII of FIG. 1.

A typical engine is shown in FIG. 1 at and a reservoir 11 for coolant is disposed in front of the engine in such position that it does not exceed the overall height of the engine, the top of which may be seen at 12 in FIG. 1. A pump 13, which is engine driven, withdraws coolant from reservoir 11 through a passage 14 and forces the coolant in a conventional manner through a pump discharge line 15 (see FIG. 2) and into the water jacket of the cylinder block from which it passes upwardly into the cylinder head all in a conventional manner and is discharged through a temperature regulator housing 16 having a conventional temperature regulated valve 17 therein. From the valve 17 the coolant flows through a return bend 18 thence downwardly through a line 19 to a heat exchanger 20. This heat exchanger may be of any conventional type, the raw water type being commonly used in marine installations. The raw water connections to the exchanger are not herein illustrated. A conduit 21 communicates between the heat exchanger and the lower portion of the reservoir 11 completing the cycle.

The purpose of the temperature regulated valve 17 is to prevent circulation of coolant through the heat exchanger when the engine is cold as for example when it is first started. Under this condition the valve 17 is closed and water from the engine is bypassed or flows directly through a line 30 betwen the cylinder head, water jacket and the reservoir 11 until the temperature of the coolant rises to the desired operating level and effects opening of the valve 17.

The reservoir is provided with a conventional filling spout and cap as shown at 31 and within the reservoir downwardly extending baffle 32 surrounds the position of the filling spout and isolates the remainder of the upper portion of the reservoir providing an expansion chamber 33 which as shown in FIG. 2 occupies both sides and the forward portion of the top of the reservoir. In this expansion chamber is a pressure actuated vent or relief valve 34 of any suitable conventional type. As shown in FIG. 3 the high level of coolant in the reservoir is equal to that in the engine head block and air in the expansion chamber 33 is at substantially the same level. Consequently, the engine cooling system may be filled through the filling spout 31 and all parts thereof will be filled as the coolant seeks a common level in them with the exception of the return bend 18 which is higher than the water level in the head block. To prevent an air lock as coolant is rising in the line 19 a small vent line 35 communicates between the upper portion of the return bend and the top of the reservoir. The bafiie 32 produces an air lock which prevents the rise of coolant in the reservoir as it is being filled to insure the presence of air in the expansion chamber 33. Therefore, because of the bafile 32 an air space or expansion chamber is provided below the normal level of liquid in the cooling system. During operation of the engine the return bend 18 is of course filled because the fluid is under pressure from the pump and as expansion takes place due to the heat of engine operation pressure in the system opens the vent 34 venting air rather than liquid from the system.

I claim:

In an engine having the usual cooling jackets a heat exchanger, a reservoir, a pump for circulating fluid therethrough, and a thermostatic valve and bypass to prevent circulation through the heat exchanger when the engine is cool, the improvement which comprises said reservoir being no higher than the engine and having a top opening filling spout and a downwardly extending bafile surrounding said spout to provide an expansion chamber in the top of the reservoir, a passageway between the engine and heat exchanger extending to a point above the engine, and an air vent line between said passageway and the top of said reservoir.

References Cited in the file of this patent UNITED STATES PATENTS 1,658,934 Muir Feb. 14, 1928 2,067,407 Milligan Jan. 12, 1937 

